Gaseous discharge device



y 9, 1952 P. w STUTSMAN 2,605,438

GASEOUS DISCHARGE DEVICE E11ed oct. 50 1948 `UNITED STATE S PATENT (SFFICE` v 1 T'his application Te1ates`t()gaseous discharge devices, and !ldre particu1a rly to grid-contr011ed gaseous discharge devices of the cold cathode type. In sotne applications of gas discharge tubes, forexan1ple, in Xlodt1ators for radar trans!1itters `or Inagnetos for deve10ping radio frequency ignition Sparks the tube is required to pass ex tre!ely high peakcurrents, fol' exa!nple, in he order of 100 ampeeS. Due to these large cur re1ts, electron enlissive !T!a terial is vaporized fron1 the cathode of the tube, Which in addition to depleting the amount of active cathode nlaeral available for supplying electrons, 'lay deposit by condensation on the pther elenents of the tube, particularly the grid These deposits, since they are electron enlissive, decrease the forward stando voltage of the tube. St8nd-off voltage in gascontr01led gadischarge tubes is deflned for use in this app1ication as that voltage which nlay be applied between the anode and cathode of the tube without breaking down the discharge path between said nde and cathode when no signal is ap lied to the grid.

ccol'dingly it is an object of the present invention to provide a gas discharge device wherein electr011 e!nissive laterial, vaporized fron1 the c9thode is largely prevented from condensing on the gid and anode eletnents of the device.

further object of the invention is to provide 9' hollow cathode structure, whereby electron enissive material vaporized from the cathode surface vvill tend to renai1in the area surroundinside of said cyunder alt app0Ximely (the middle thereo. This disc is provided with suit able holes |2 to allow the passage of gas Teadily 'therethrough. ''he upper )()1'tion of the cylhlder cont9ains a Teserve supply0f gas, vvhile the 10-vel' portion contains the elements df the tube.

The cathode of the tube which is rigidly attached to the disc comprises a cupshped or tubular !Tle!nber |3, Which hs been filled vvith aan electron enissive nlaterial said electron enissive nlaterial is preferably al nixture of finely divided caesium chloride and alunlinum which has been packed into the cup l3 with sumcient pressu!'e to approach crystallization of the Ina'- terial l#. A second Gup-Shaped !!lenlber 5 is csely iitted inside the cup-shaped Inember |3 nrmly pressing against the material H. The bw() cupshaped Inel!bers are !Ily attached to gethe1' and to the bottorn side of the disc ll, for

example by welding such that the bottom of the cup-Shaped member -|3 oints downward These cup-shaped members are of metal and the mem ber l3 is of al nlaterial which is electron elnissive surrounds the cylindrical cathode cup n1e1ber the cup-shaped Inenlber l3 and an outside dia!n eter S0Ingwhat sxnaller than the inn'er dialeter of the envelope to pern1it the p ssage 0f a gaseous nledium between the envelope and A further object of the invention is to provide leferring now to Fig. 1 there is shown an elec tron disch rge dgvice having a Ineta1 envelope l. vvich is cylindical in shape. 'Illis cylindrical envelpe is separated info two cylindrical spaces the ceraniic cylinder IT.

hole |8 1S drnled in the ceralnic cylinder concentric with the hole in the botto!n of the cup- Shaped member |3. This hole m is of somewhat larger dianleter than the hole IG, thus exposing a' smn ring of the cup-Shaped member tlTough said hole l8, the rest of the cup-Shaped Tle!!1ber l3 being shielded by the ceranlic cylin de!'. '];he lowel' sufce of the ceranic Inenber contains a cylilldrical recess concentric with the recess acc0nxnodati1g the cathode nlen]ber, and of a slightly larger diameter This recess is of 9' sumcient depth tha'ta' small ring of ceramic material remains hetween the two re cesses, Said ring c011taining the hole l8.

POSitioned in Said lower recess is a cylindrical grid nlenlber |9 which is preferably of graphite and whose outside diameter is sonlewhat snlaller than the lower receSs into which it fits, to auow 

